The present invention relates to a percussion drill bit for drilling bores in rock. A typical percussion drill bit comprises a steel drill body, means at one end of the drill body for connecting the bit to a percussive unit such as a drill string for a jack hammer or a down-the-hole hammer, and a plurality of buttons embedded in the other end of the drill body. The present invention also relates to a regrind able button for use in said drill bit.
Each button comprises a cemented carbide body having a rear mounting portion embedded in the drill body and a front end protruding from the drill body.
Known drill bits that are provided with non-enhanced cemented carbide buttons such as disclosed in EP-B1-886 715 have disadvantages in that they wear prematurely and have slow penetration rates. Furthermore regrinding of conventional buttons becomes unstable. Other known drill bits are shown in U.S. Pat. No. 3,788,409 and U.S. Pat. No. 6,220,376.